Actuallt kinda depends
Using three VERY different tech levels but..
assuming "space" battles
The big "losers" so to speak (imho) would be 40ks Navy.
The ships are huge, sure, but really not all that well armed for their size.
(at least vis a vis the other two)
Star Wars/Star trek is slightly more difficult, I'd actually argue that the lasers etc in Star Wars are
considerably more powerful than lasers in ST, Not sure if they'd have phaser level power or not, but they'd be close.
As for F14's/ZYcs -dunno, if one thing is completely screwed up in SFB it's their implemention of fighters.
While I understand the gaming reason behind it , SFB has neither the number of fighters or the individual capabilities at a level that actually makes sense.
As for ANY battle that takes place involving troops, I'd have to go with
1) Space Marines
2) StormTrooper Legions
3) Imperial Guard
995) Whatver the heck Star Trek uses for security detail.